A mechanical device has a wearout time distributed normally with a mean of 1100 hours and a standard deviation of 50 hours. Find the values that constitute the central 95% of the wearout times.
A mechanical device has a wearout time distributed normally with a mean of 1100 hours and...
The time in hours for a worker to repair an electrical instrument is a Normally distributed random variable with a mean of μ and a standard deviation of 50. The repair times for 12 such instruments chosen at random are as follows: 183 222 303 262 178 232 268 201 244 183 201 140 Part a) Find a 95% confidence interval for μ. For both sides of the bound, leave your answer with 1 decimal place. ( , ). Part b) Find...
The income of trainees at a local mill are normally distributed with a mean of $1100 and a standard deviation of $150. What percentage of trainees earn less than $1200 a month?
Time to finish a final exam is normally distributed with mean 0.8 hours and standard deviation 7 minutes. What is the first quartile of the time distribution?
The time to failure of a mechanical component (in a vehicle) is normally distributed with a MTTF = 20,000 miles and a standard deviation of 5,000 miles. Since installing this component, it has not failed in the first 20,000 miles. What is the probability that it does not fail in the next 10,000 miles?
A "KRISPY CREAM DONUT" has a normally distributed lifetime with Mean = 10 hours and a Standard Deviation 3 hours. What is the probability that having the donut survived 10 hours, it will become bad within the following 10 hours? Your Answer: Answer A "KRISPY CREAM DONUT" has a normally distributed lifetime with Mean = 10 hours and a Standard Deviation 3 hours. What is the probability that having the donut survived 10 hours, it will become bad within the...
The number of sleep hours for adults is normally distributed with mean 7 hours and standard deviation 1.7 hours. How large a sample should be selected if we we wish our estimate to be correct within 30 minutes with 95% confidence? a) 44 b)45 c)12 d)11
Suppose that the time duration of a minor surgery is approximately normally distributed with mean equal to 800 seconds and a standard deviation of 40 seconds. Find the probability that a random sample of 16 surgeries will have average time duration of less than 775 seconds. Use the central limit theorem 9-
1. The patient recovery time from a particular surgical procedure is normally distributed with a mean of 5.9 days and a standard deviation of 2.1 days. What is the probability of spending more than 2 days in recovery? (Round your answer to four decimal places.) 2. The patient recovery time from a particular surgical procedure is normally distributed with a mean of 5.8 days and a standard deviation of 2.4 days. What is the 90th percentile for recovery times? (Round...
15) Assume that z scores are normally distributed with a mean of 0 and a standard deviation 15) of 1. If P(z> c) 0.109, find c. olve the problem. 16) 16) Scores on an English test are normally distributed with a mean of 37.4 and a standard deviation of 7.9. Find the score that separates the top 59% from the bottom 41% 17) Suppose that replacement times for washing machines are normally distributed with a 17) mean of 10.9 years...
A DC battery has a time to failure that is normally distributed with a mean of 30 hours and a standard deviation of 4 hours. (a) What is the 25 hour reliability? (b) When should a battery be replaced to ensure that there is not more than a 5% change of failure prior to replacement? (c) Two batteries are connected in parallel to power a light. Assuming that the light does not fail, what is the 35 hour reliability for...